1. b

2. TOPIC 9
WEATHERING & EROSION

3. The transport of broken down rock material
Weathering
The breakdown of rock material
Erosion
The transport of broken down rock material
Vs.

4. Breakdown of rock material without changing the chemical makeup of the rock.
Example: smashing chalk with hammer.
Breakdown of rock material by changing the chemical makeup of the rock
Example: dissolving chalk in acid

5. Frost Action- water expands when frozen
Plant Action
Abrasion
Oxidation
Carbonation
Hydration

10. Cape May “Diamonds”

12. FACTORS AFFECTING WEATHERING RATES
Particle Size
Composition of Rock
Climate
Exposure

13. Particle size:
As particle size increases, weathering rate decreases. (indirect relationship)
This is due to an increase in surface area.
rate
size

14. Composition:
Some rocks are more resistant to weathering than other rocks.
Rocks that are more resistant will weather slower than those that are less resistant.
Less resistant
More resistant

15. You might also see it like this…

21. Climate: Warm climates - Chemical weathering
Cold climates Physical weathering
As moisture increases, weathering rates increase or…
“Wetter is Better !!!”
a warm, moist climate will have greater weathering rates than a warm, dry climate

23. Cleopatra’s Needle

25. Exposure:
As a rocks exposure to the Earth’s surface increases, the weathering rate increases.
Im OK!

26. *GRAVITY is the driving force behind erosion !

27. The 5 Agents of erosion are…
Streams
Waves
Wind
Gravity
Glaciers

28. Stream Erosion The most predominant agent of erosion. Why?
Methods of transport:

29. Stream velocity depends on…
Gradient (slope) as slope increases, velocity increases.
Discharge (amt. of water in the stream) as discharge increases, velocity increases.

30. Velocity vs. Sediment When the velocity increases…
The amt. of sediments carried increases
The size of the sediments carried increases.

33. Erosion
Frost action
Oxidation
Caves
Abrasion
Plant action
Hydration
Weathering
Discharge
Meander
Delta
Alluvial fan
Horizontal sorting

35. Streams move fastest… Just below the surface
In the center of the channel

36. Meanders * Water moves fastest on the outside of meanders.
High KE More Erosion
Low KE Less Erosion

39. DELTA: Sediments deposited at the mouth of a stream.
Sediments are deposited because the stream velocity decreases abruptly.

40. Horizontal Sorting
The sediment size decreases as the distance from the mouth increases.
Largest Sediments
Smallest sediments

42. Alluvial Fan (land delta)
Fan shaped deposit formed when streams flow off of mountains onto more level land.

46. Stages of Stream Development

47. Stream Sediments
Sediments deposited by a stream are usually sorted, rounded and smooth.

48. Narrow V-shaped
Downcutting
Swift water
Steep gradient
Erosion is dominant

50. Wide meanders and oxbow lakes
Wide floodplain
Low velocity
Low gradient
Dynamic equilibrium between erosion and deposition

53. Glaciers Large mass of moving ice. Continental vs. Mountain glaciers.
Ice forms from the pressure caused by the weight of the accumulating snow.

55. Glacial features: Till- sediments transported by glaciers
Sediments are Unsorted and Angular.

58. Glacial features: Till- sediments transported by glaciers
Sediments are Unsorted and Angular.
Striations- scratches and grooves in bedrock.

62. Glacial features: Till- sediments transported by glaciers
Sediments are Unsorted and Angular.
Striations- scratches and grooves in bedrock.
Erratics-large boulders deposited by a glacier that DO NOT match the local bedrock.

67. U- Shaped Valleys

68. Stream Valley
Glacial Valley

69. Moraines

71. Other Features:
Drumlins

74. Other Features:
Drumlins
Eskers

79. Long Island- Terminal Moraine

80. Finger Lakes

81. Other Features:
Drumlins
Eskers
Kames
Long Island
Finger Lakes

82. Crevasses

83. Valley Glacier

84. Continental Glacier

85. Till

86. Erratics

87. Striations

88. Drumlins

89. Eskers

90. Kettles

91. Kames

92. Outwash Planes

93. Outwash

94. Moraine

95. WIND EROSION Wind transported sediments are… 1. Small 2. Dry
3. Loose (free to move)
** Sediments are frosted and pitted

96. Features: Wind erosion may cause abrasion.
ex: Arches, toadstools, ventifacts, desert pavement

97. Deflation

98. Sandblasting
Winds blow sand against rocks causing abrasion.

103. Dune:
Deposit of windblown sand.

104. WAVE EROSION
Sediments are transported due to the energy created by breaking waves.

112. Mass Movement:
Any variety of erosion and/or deposition done directly by gravity.
Examples:
Rock slides
Avalanches
Slump
Creep
Deposits are unsorted and angular.

118. Mr. Arcuri
John Deere
Cafeteria
Mr. Egresits
Stewarts
Golden Knights
Mr. Andrews
Mr. Goodelle